It will be a nice result after the wait. I suspect you're a bit fidgity while waiting. I don't think I'd like a 28 day wait for a rifle- nor a handgun. Not happening here - yet.

The short throat on your 3-1/4" chamber probably makes it about the same length as the .458's actual throat.

In comparrison, my .458 2" had a 3/8" leade, which allowed the same overall length as if the case was 2.375" long. this allowed the heavy loads I used, running 500gr. to 2,060 without running into pressure problems.

The same goes for a long leade in a .458 WMag. Seating the bullet out as far as possible will help accuracy and increase case capacity same as if the case was actually longer.

Knowing the actual dimensions of one's chamber is quite important when working up loads.